1. Field of the invention
This invention relates to a cartridge device for a recording medium holding a recording medium including a disc-shaped recording medium, such as a magnetic disc, a magneto-optical disc or a floppy disc, or a magnetic tape, in its main cartridge body portion. More particularly, it relates to a cartridge device for a recording medium having a cover member, such as a lid member or a shutter member, for opening or closing a recording/reproducing aperture provided in the main cartridge body portion.
2. Description of the Related Art
In a cartridge device for a recording medium, holding a recording medium, including a disc-shaped recording medium, such as a magnetic disc or a magneto-optical disc, or a magnetic tape, in its main cartridge body portion, usually a recording/reproducing aperture is formed in the main cartridge body portion in order to permit the magnetic head or the like to be intruded into the inside the cartridge device, while a lid member as a shutter member for opening or closing this recording/reproducing aperture is assembled in position. By this shutter member and the lid member, the cartridge device for a recording medium prevents dust and dirt or foreign matter from entering the interior of the cartridge main body via recording/reproducing aperture to become attached to and damage the recording medium to lower recording characteristics.
Referring to FIGS. 1 and 2, a magnetic disc cartridge device 50 has a cartridge main body portion 51 which is combined from an upper half 52 and a lower half 53 each formed in the shape of a rectangular shallow saucer. In the cartridge main body portion 51 is rotatably housed a magnetic disc 1.
Referring to FIG. 2, arcuate-shaped guide wall sections 54 are formed upright on the facing inner sides of the upper half 52 and the lower half 53. When assembled together, these guide wall sections 54 are abutted to each other to define a disc housing 55 in which to rotatably hold a magnetic disc 1. The lower half 53 is formed with a hub opening 53a mounted at a mid portion of the disc housing 55 to cause the center hub 2 of the magnetic disc 1 to be exposed to outside.
The cartridge main body portion 51 has its front side opened for defining a recording/reproducing aperture 56 to permit entrance of the magnetic head on the side of the recording/reproducing apparatus. On this cartridge main body portion 51 is mounted a lid member 57 for opening/closing the recording/reproducing aperture 56. The lid member 57 is formed as a substantially rectangular form by having a horizontally elongated major surface section 57a of an outer size sufficient to close the recording/reproducing aperture 56 and lateral surface sections 57b, 57c integrally formed with both lateral sides of the major surface section 57a at right angles therewith. This lid member 57 has on the inner surfaces of the lateral surface sections 57b, 57c integral co-linear supporting shafts 58a, 58b.
The lid member 57 is rotatably assembled on the cartridge main body portion 51 by having supporting shafts 58a, 58b fitted in axial holes formed by combining U-shaped recesses formed on the abutting upper edges of both lateral side sections of the upper half 52 and the lower half 53. The lid member 57 usually closes the recording/reproducing aperture 56 under the force of a torsion spring, not shown. If the magnetic disc cartridge device 50 is loaded on the recording/reproducing apparatus, the lid member 57 is rotated by an opening member, not shown, against the force of the torsion spring for opening the recording/reproducing aperture 56.
Into the magnetic disc cartridge device 50 is intruded a magnetic head device on the side of the recording/reproducing apparatus via the opened recording/reproducing aperture 56 so as to face the major surface of the magnetic disc housed therein. In the magnetic disc cartridge device 50, the magnetic head device records or reproduces information signals recorded on the magnetic head device.
In a tape cartridge device 60, used in a video tape recorder or audio tape recorder, an upper half 62 and a lower half 63, each formed in the form of a rectangular shallow saucer, are assembled together to form a cartridge main body portion 61. In the inside of the cartridge main body portion 61 are rotatably housed a pair of tape reels 3a, 3b. In the tape cartridge device 60, a magnetic tape 4 is reeled out from the tape reel 3a to run on the front surface of the cartridge main body portion 61 so as to be taken up on the opposite side tape reel.
The cartridge main body portion 61 is formed with a recording/reproducing aperture 65 by providing an opening in its front surface along which runs the magnetic tape 4. A lid assembly 64 is rotatably mounted on the cartridge main body portion 61 for opening/closing this recording/reproducing aperture 65. The lid assembly 64 is made up of a front side lid and a rear lid, not shown in detail, for defining a running space for the magnetic tape 4. Referring to FIG. 3, the lid assembly 64 usually closes the recording/reproducing aperture 65 under the force of a torsion spring, not shown. When the tape cartridge device 60 is loaded on the recording/reproducing apparatus, the lid assembly 64 is rotated by an opening member against the force of a torsion spring for opening the recording/reproducing aperture 65.
Into the tape cartridge device 60 is intruded a magnetic head device on the side of the recording/reproducing apparatus from the opened recording/reproducing aperture 60 so as to have a sliding contact with the magnetic tape 4 running on the front surface of the cartridge main body portion 61. In the tape cartridge device 60, the information signals are recorded or reproduced by the magnetic head device.
In a disc cartridge device 70, holding a magneto-optical disc 5, an upper shell 72 and a lower shell 73, each in the shape of a rectangular shallow saucer, are combined to form a cartridge main body portion 71, as shown in FIG. 4. The cartridge main body portion 71 is formed with a hub opening 73a for causing a center hub 6 of the magneto-optical disc 5 to face to outside, while a recording/reproducing aperture 74 is formed in the major surfaces of the upper shell 72 and the lower shell 73.
The recording/reproducing apparatus 74 is a rectangular opening for causing portions of the front and rear surfaces of the magneto-optical disc 5 radially to be exposed to outside. For example, an optical pickup of the recording/reproducing apparatus is intruded from the upper shell 72, while a magnetic head device is intruded from the lower shell 73 for facing the major surface of the magneto-optical disc 5. The recording/reproducing aperture 74 is usually closed by a shutter member 75 slidably assembled on the cartridge main body portion 71.
Although not shown, the shutter member 75 is formed substantially in a U-shape by having front and back side shutter portions large enough to open or close the recording/reproducing aperture 74 and a connecting portion interconnecting these shutter portions. In the shutter member, the shutter portions are positioned in slide guide recesses 76 formed in the major surfaces of the upper shell 72 and the lower shell 73, whilst the connecting portion is extended along the front side of the cartridge main body portion 71. A driving piece 77 engaged in a guide recess formed in the front surface of the cartridge main body portion 71 is mounted on the shutter member 75. This shutter member 75 is combined with the cartridge main body portion 71 for usually closing the recording/reproducing aperture 74 under the force of a spring, not shown. The shutter member 75, now provided, is configured for maintaining the recording/reproducing aperture in the closed state by a mechanical lock mechanism, not shown.
When the disc cartridge device 70 is loaded on the recording/reproducing apparatus, the driving piece 77 is moved along the guide recess against the force of the spring for sliding the shutter member 75 in the slide guide recess 76. This opens the recording/reproducing aperture 74 of the disc cartridge device 70 so that the optical pickup device and the magnetic head device on the side of the recording/reproducing apparatus are positioned for facing the front and back sides, respectively, of the magneto-optical disc 5 via the opened recording/reproducing aperture 74.
In the disc cartridge device 70, information signals recorded on the magneto-optical disc 5 are reproduced by an optical pickup device. Also, in the disc cartridge device 70, information signals are recorded on the magneto-optical disc 5 by the optical pickup device and the magnetic head device.
In the above-described conventional cartridge device for a recording medium, a recording/reproducing aperture is formed in the cartridge main body portion, while there is mounted the cover member, such as the lid member or the shutter member, for opening/closing the recording/reproducing aperture. The cover member operates for preventing dust and dirt or foreign matter from being intruded into the inside of the cartridge main body portion via the recording/reproducing aperture as described above. However, in the conventional cartridge device for a recording medium, since the cover member is in frictional sliding contact with the major surface of the cartridge main body during its operation, there is generated cutting dust which is intruded into the inside of the cartridge main body so as to be affixed to the recording surface of the recording medium to affect the recording/reproducing characteristics.
That is, in the magnetic disc cartridge device 50, shown in FIGS. 1 and 2, the lid member 57 is rotatably combined with the cartridge main body portion 51 by supporting shafts 58a, 58b on fulcrum portions 57b, 57c being fitted in axial holes in the cartridge main body portion 51. In the magnetic disc cartridge device 50, an axial hole in the cartridge main body portion 51 is passed through lateral surface sections of the upper half 52 and the lower half 53 so as to directly face a disc housing section 55, as shown in FIG. 2. In the magnetic disc cartridge device 50, the inner wall of the axial hole is rubbed against the outer rim portions of the supporting shafts 58a, 58b to produce dust on opening/closing the lid member 57.
In the magnetic disc cartridge device 50, there are occasions wherein the generated dust is intruded into the inside of the cartridge main body portion 51 to become affixed to the surface of the magnetic disc held therein. In the magnetic disc cartridge device 50, the magnetic head device is intruded into a narrow space defined between the magnetic disc 1 of the cartridge main body portion 51 and the upper half 52, while the gap between the magnetic disc 1 and the magnetic head is as small as 0.05 .mu.m. On the other hand, the generated dust is generally 1 to 20 .mu.m.
Therefore, in the conventional magnetic disc cartridge device 50, the risk is high that serious accidents, such as recording/reproducing dropout of information signals or destruction of the magnetic head, may be produced due to the dust and dirt. This phenomenon becomes outstanding on prolonged use of the magnetic disc cartridge device 50 to affect the operating reliability.
Also, in the tape cartridge device 60, shown in FIG. 3, supporting shafts are integrally formed on both lateral sides of the lid structure 64, which is rotatably assembled on the cartridge main body portion 61 for rotatably assembling the lid structure 64 on the cartridge main body portion 61. Thus, on rotating the lid structure 64, the inner wall section of the axial hole is rubbed against the outer periphery of the supporting shaft for producing dust and dirt.
With the tape cartridge device 60, the produced dust is intruded into the inside of the cartridge main body portion 61 to become affixed to the surfaces of the magnetic tape 4 placed around tape reels 3a, 3b or to be intruded between neighboring layers. Moreover, the magnetic disc cartridge device 50 suffers from a drawback that the generated dust is also intruded into the recording/reproducing apparatus for affecting the magnetic head device or various other components. Thus, in the tape cartridge device 60, the magnetic tape 4 tends to be damaged by this dust or problems such as dropout of information signals or destruction of the magnetic head are raised. There is also raised such a problem that the generated dust be intruded into the recording/reproducing apparatus to affect the magnetic head device or other components.
In addition, in the disc cartridge device 70, shown in FIG. 4, since the shutter member 75 is slid in contact with the inside of a guide recess 76 to open/close the recording/reproducing aperture 74, the shutter member 75 is rubbed against the bottom surface of the slide guide recess 76 to produce dust and dirt. This dust and dirt is forwarded from the bottom surface of the slide guide recess 76 via the recording/reproducing aperture 74 into the inside of the cartridge main body portion 71, with movement of the shutter member 75, so as to become affixed to the major surface of the magneto-optical disc 5 held therein.
Thus, in the magnetic disc cartridge device 70, the risk is high that serious accidents, such as recording/reproducing dropout of information signals or destruction of the magnetic head, may be produced due to this dust. There is also raised such a problem that the generated dust be intruded into the recording/reproducing apparatus to affect the magnetic head device or other components.
For solving the above problem, it is contemplated in the above-described cartridge devices for recording mediums to charge a highly viscous lubricant, such as grease, between the inner wall sections of the shaft openings of the cartridge main body portions 51, 61 and supporting shafts of the lid members 57, 64 or between the inner surface of the shutter member 75 and the bottom surface of the slide guide recess 76. The lubricant performs the role of reducing rotational and sliding resistance between these components to suppress dust generation to capture the generated dust to prevent it from flying.
However, this lubricant is scattered to inside and outside of the cartridge main body portion to become affixed to the recording medium or the magnetic head to disable recording/reproduction of information signals. Moreover, the lubricant leaks out of the disc housing section to cause the disc-shaped recording medium to be bonded to its bottom surface to disable its rotation. In addition, the lubricant raises such a problem that the shutter member shall be bonded to the bottom surface of the slide guide recess to disable its operation. For fear of these serious problems, the conventional cartridge device for a recording medium cannot use lubricants for rotation and sliding of the lid member.